1. Field of the Invention
This invention relates generally to systems for precisely controlling the delivery of liquids, and is particularly suited for although not limited in use to lawn treatment systems for alternatively applying either a water diluted fertilizer, or a mixture of the water diluted fertilizer and a liquid pest control product, e.g., an insecticide or pesticide.
2. Description of the Prior Art
Lawn treatment systems of the above-described type are known, as evidenced for example by the disclosure in U.S. Pat. No. 4,609,149. Such systems are typically truck or trailer mounted, with storage tanks containing the liquids to be dispensed, and pumps for delivering the liquids via separate hoses to a portable applicator gun which may be operated to apply a single liquid, e.g., water diluted fertilizer, or a mixture of the water diluted fertilizer and the liquid pest control product. While such systems operate in a generally satisfactory manner, they lack adequate means for precisely controlling the amount of pest control product being delivered to the applicator gun. This can result in either inadequate treatment, which allows insects and weeds to flourish, or over treatment, which can be harmful to the grasses being cultivated
The objective of the present invention is to address this shortcoming of the prior art, in addition to providing other important advantages.